Fastener for bubble caps



P. DE BIE FASTENER FOR BUBBLE CAPS July 2, 1957 2 Shee'ts-Sheet l FiledAug. 17, 1954 FIG.

FIG.

INVENTOR:

PIET DE BI HS TTJRNEY July 2, 1957 I P, DE B15 2,797,907

FASTENER FOR BUBBLE CAPS Filed Aug. 1'7, 1954 2 Sheets-Sheet 2 'lOb Flsf Fla? INVENTOR PlET DE BlE HIS ATTORNEY 2,797,907 Patented July 2,195.7

FAS'YENER FR BEUEBLE CAPS Piet de Bie, The Hague, Netherlands, assignerto Shell Development Company, New York, N. Y., a corpora- Y Thisinvention relates to a fastener or hold-down for securing a bubble capover an opening in a contacting tray deck,I e. g., a bubble tray or deckof a fractionating tower, and to the combination of such a deck with abubble cap and the fastener. More particularly, the invention relates toa fastener that includes an upright stem or fastening bolt and atransverse support for engaging the edge of the opening and lower faceof the deck when in place, said fastener being adapted both forinsertion into and removal from the opening from a position above thedeck without the services of a workman beneath the deck, and beingfrictionally retained to the de k against falling during assembly to anddisassembly from the deck.

Various hold-downs for bubble caps have heretofore been described. One(U. Patent No. 2,338,928), includes a central stern and a transversesupport having shouldered arms that are alternately provided with lugsat their lower and upper sides for engaging the lower and uppersurfaces, respectively, of the tray deck and thereby securing the stemagainst both upward and downward movements. During installation, thehold-down is tilted and hooked into the deck opening to place all armsinitially beneath the deck; the stem is then righted and raised with thestem centered in the opening. The arms that have their lugs at ti e top,having the` ends rounded off, ex inwardly upon engaging the edge of theopening so as to pass through the latter and thereafter spring outwardswhen their lugs emerge above the deck.

An important disadvantage of this construction is the dilliculty inremoving the hold-down from the deck; this operation involves flexingthe arms whose lugs are above the deck manually to pass the lugsdownwards through the opening. lt is obvious that this operationinvolves a considerable amount of time and labor when applied to adistillation or scrubbing tower having a large number of bubble caps.Further, such a hold-down can be .used only on a tray deck presenting atthe edge of the opening a deck thickness that corresponds to thevertical interval between the upper and lower lugs; hence decks ofdifferent thicknesses require correspondingly dimensioned holddowns.

Another hold-down construction (U. IS. Patent No. 2,443,812) uses aninverted Lil-shaped spring clip with out-turned lugs at the bottoms ofthe spring arms, the said arms pressing against the vapor riser forfrictional support to hold the fastening bolt against falling during asnsembly and disassembly. One drawback of this construction is that thespring clip requires a vertically enlarged contacting surface, such asthe inner face of a riser tube, and cannot, therefore, be installed in asimple opening in a plate forming a deck. Another drawback is that,because the arms of the spring clip terminate in lugs that engage theunder side of the deck, the clip can be removed upwards from the openingonly by detaching or bending the lugs, which must be done from aposition beneath the deck; two men are, therefore, required for removingbubble caps held down with such clips.

It is an object of the invention to provide an improved hold-down forbubble caps that, as well as the bubble cap held thereby, can beinstalled and removed by one Workman from a position above the tray deckwithout the necessity of flexing any arm or the like by a specialmanipulation.

A further object is to provide a hold-down for bubble caps that can beinstalled within an opening in a plate-type of tray deck of anythickness, working only from a position above the tray, for centering orotherwise correctly positioning the fastening bolt or stem within theopening and frictionally securing the hold-down within the openingagainst falling during assembly and disassembly.

In summary, the improved hold-down comprises an upright fastening stemto the top of which the bubble cap is secured and a transverse resilientsupport secured to the stem and comprising a plurality of arms havingshoulders providing lugs adapted to engage the under side of the deck,said arms having lateral retaining surfaces adapted for frictionalengagement with the inner edge of the opening in the deck and havingearn surfaces for flexing the support by engagement with the deck whenit is moved upwards through the opening, all parts of the support abovethe said retaining surfaces being situated within a closed planegeometric ligure, such as a circle, that is smaller than the similarfigure enclosing the several retaining surfaces, whereby the support isretained frictionally in the opening solely by the resiliency of thesupport. The geometric relation between the stem and support is suchthat the hold-down can be tilted and inserted into the deck opening fromthe top to bring the support entirely beneath the deck. The device isthen moved to position the stem vertically and center it, and drawnupwards into the deck opening to flex the support inward and engage theretaining surfaces to the inner edge of the opening. The device can beremoved from the deck by simply pushing it down to free the support fromthe edge of the opening, tilting it, and drawing it up through theopening.

Various embodiments of the invention are illustrated in the accompanyingdrawings forming a part of this specilication, wherein:

Figure 1 is a sectional view taken on a vertical plane through thediameter of the opening in a tray deck and showing a bubble cap fastenedto a tray deck with the hold-down according to the invention;

Figure 2 is a bottom plan view, looking in the direction of the arrows 22 in Figure l;

Figure 3 is a sectional view taken on a vertical plane through thediameter of the opening and illustrating the insertion of the hold-down;

Figure 4 is a sectional View taken on the section line 4 4 of Figure 2and showing the hold-down in operative position;

Figures 5, 6 and 7 are bottom plan views of three alternativeconstructions; and

Figure 8 is a perspective view of an arm of a support according toFigure 5 or 6.

Referring to the drawings in detail, and particularly to Figures 1-4,the bubble cap l is supported by vertical spacer plates 2 that arepositioned in notches in the upper rim of a tubular riser 3. The bubblecap is situated over a circular opening 4 formed within a tray deck 5,against which the bottom of the riser 3 is seated to support the bubblecap upwardly. The bubble cap is fastened by a fastening stem or bolt 6which is permanently fastened at the bottom to a flexible, transversesupport 7, the said stem and support together constituting thehold-down. The top of the stem is threaded to receive nuts S which bearon a washer 9 for holding the bubble cap in place.

agregara' ThesupportI 7l (-see Figure 2) consists ofV four' hori'zontal, flexible arms formed by two resilient metal strips that are thinin relation to their vertical dimensions and are bent toward each otherat their intermediate parts', atf which they are fastened't'o eachother'and to the bottom of the stem 6, e. g., by welding. The arms thusform an tei-shapedy support, The outermost parts advantageouslyintersect the edge of the opening at an angle to the radius, as shown,so as to be readily defi'ectable inwardsin" the manner to be describedpresently. The'shape of the support, when in the relaxed state, prior toinstallation, isshown in chain lines in Figure'Z. The end of'each'armisshouldered to provide a lug 11 at the bottom thereof and alateralretaining surface 12 extending vertically from thel lug. A cam surface13 extendsv upwards from the retaining surface and is inclined generallytoward the steme6; thecam surface may bestra'ight, as" shown, orlrounded as shown in Fig. 8.

Referring to Figure 4, three steps can-be distinguished in the supportin its installed position when'viewed in side elevation.: (a), Thelowest'step is formed by the lugs 11, the ends of which may becircumscribed by a circle of diameter D1 which is larger than thediameter of the opening 4; hence, the lugs engagethe lowerfaceof thetray deck to hold the stem 6 down and secure the riser 3 and bubble cap5 when the nuts 8 are tightened. (b)

The second step is fonned'by the retaining surfaces 12,v

which fall within a circumscribed circle of diameter D2 equal to thediameter of theV hole 4. Prior to being locked inplace, i; e., in aVresiliently released condition as-shown in chain lines in Figure 2, thediameter D2 of the circumscribed circle enclosing the retaining surfaces12 exceeds slightly that' ofthe opening 4. (c) The third step, formed bythe cam surfaces 13, has circumscribed circlesof diameters that diminishtowards the top tov a; limiting diameter D3 which is much smaller thanthe diameter ofV the opening 4, bothin thelocked and relaxed positionsofthe. support. It followsY that all parts of the support above thevertical retaining surfaces 12 are situated'within a circlethat issmaller than the circle enclosingl the retaining surfaces.

Installation of the hold-down and mounting of the bubble cap can becarried out in the following manner:

The operator, working above the tray 5, inserts the hold-down into theopening 4 with the stem 6 inclined to the vertical, as shown in Figure3, to hook the ends of two parallel arms 10 atv one side of the stemunder the tray and then swings the device to move the stem into verticalposition so that the support-7 is entirely below' the tray. He thencenters the stem approximately and pulls up on it. Engagement of the camsurfacesV 13 with theeinner edge of the opening 4-centers thestemaccurately and causes flexure of the arms from the chain linepositions to the solid line positions (Figure 2), which reduces D2, thediameter of the circle enclosing the retaining surfaces 12, toa valueequal to the diameter of the opening 4. When the lugs 11 engage theunder side of the tray deck 5 the supportv 7 is resiliently locked tothe deck. The stern 6 may now be released without its falling throughthe opening 4, after which the riser 3 with the spacers 2 and the caplare placed over the opening' and around the stem 6. The upper part ofthe stem then extends through the cap 1 and the washer 9 and nuts 8 areapplied.

When dismantling the bubble cap, the nuts 8 and washer 9 are detachedand they capand riser are lifted and removed, while the stem 6remainslocked in the opening 4; the'reafterthe hold-down is removed with a'continuous motion' of the hand, which includes a downwardmovement tomovefthe support entirely beneath thedeck, tiltingv theV hold-down, andlifting it, in reverse of-v themovements described previously inconnection with.Figure 3.

The support 7 may also be constructed in various-ways; care should,however, be taken to insure that it can pass throughtheopening 4'fwhenAthe stern 6is in' an oblique position and can engage the edges of theopening when the stem is in a central, vertical position. It is notnecessary that the support have more than two arms, that all the arms beflexible or shaped identically or symmetrically, that all cam surfaces13 be inclined away from the periphery, although all of thesecharacteristics are highly advantageous in affording a better centeringaction and in providing a support having maximum durability and securityfor a given weight and flexibility. Thus, it is, broadly, sufficientthat two diametrically opposed parts of the support or three partsdisposed at the apices of a triangle and` suitably distributed about theperiphery of the opening have such retaining surfaces, and that one ormore of the cam surfaces 13:` beinclined so that the plane geometricfigure enclosing the retaining surfaces (a circlein the caseillustrated) is reduced when the support is pulled'upwards through theopening. As regards flexibility, it is highly advantageous, althoughagain not essential, that the arms intersect the edge of the opening atan' inclination tothe radius, as shown, so thatthey are readilydeflected horizontally by the action of the cam surface. Finally, eacharm may provide more thanV one lug for engaging the under side of thedeck and/ or more than one retaining surface for resiliently engagingthe interior surface of the deck opening. Examples are:

In Figure 5 the stern 6 is attached to a support having two identicallyshaped arms 10a that are also'thin, -vertically elongated metal stripsgenerally J-shaped in plan. As shown in Figure 8, the upper part of themetal is cut away from the radially outermost part of each arm to leavean abutment or lug' 11a and two retaining edges 12a, 12b, that mergeinto'v inwardly sloping cam surfacesv 13a, 13b that Iare rounded' with arad of curvature R'. The diametersY D1, Dz and D3 of thecircumscribedcircles are indicated; they havethe'signic'ance previously described forthe first embodiment. The hold-down is installed and removed in the samemanneras above.

InFigure 6 the construction is as was described for Figures 5 and 8?'but th're'e'armsl 10a of identical construetion are' provided.

In Figure 7 the support has'two identically shaped arms 10b formingloops, thesupportV as a whole being -shaped in plan. Each arm againprovidesa pair of retaining sur-Y faces and a pairof cam surfaces,differing from Figure 8 only in that'bo'th ends of the strip areattached to the stem 6.

Iclaim as my invention:

1. A hold-down for fastening a bubble cap over an opening in acontacting trayy deck, comprising an upright fastening stem adapted forconnection at the top thereof to the bubble cap and a transverse,resilient support.' secured to the bottom of the stern so as to permitdownward Vpassage of the support through said opening from above thedeck and upward passage therethrough from below yin' the'v undeformedstate of the support andy having aV plurality of upwardly directedabutments dlsposed to engage the under side of the deck to limit upwardmovement of the support, a plurality of lateral retaining surfaceson theresilient support urged resiliently outwards forfrictional engagementwith the interior surfaceV of said opening, and cam surfaces above saidretaining surfaces on the support merging therewith to move saidretaining surfaces resiliently inwards by engagement of said camsurfaceswith said interior surface of the opening, all parts of thesupport above said retaining suri faces being situated inwardsV withrespect tothe retaining surfaces, whereby said support is restrainedagainst downward movement during' assembly and disassembly solely bysaid resilient, frictional engagement.

2. A hold-down vaccording to claim 1 wherein saidsup'- port comprises aplurality of resilient arms formed of. stripsv that are verticallyelongated and laterally flexible, at least two of said-armsbein'gshouldered at their outer ends to provide lugs constituting thesaid upwardly directed abutments, the end of each said arm immediatelyabove the lug constituting one of said retaining surfaces, the part ofeach arm above said retaining surface being inclined generally towardthe stem to constitute the said cam surface, and the part of each stripadjoining the said cam surface thereon being inclined to the radialplane through said retaining surface thereon.

3. A hold-down according to claim 2 wherein the support consists of fourarms grouped about the stem in the form of an H.

4. A hold-down according to claim 2 wherein said arms are rounded attheir outer ends and each arm has a pair of spaced retaining surfacesand an intermediate lug.

5. A hold-down according to claim 4 wherein said arms are generallyJ-shaped.

6. A hold-down according to claim 4 wherein said arms are closed loopshaving both ends thereof joined to said stem.

7. A hold-down for fastening a bubble cap over a circular opening in .acontacting tray deck, comprising an upright fastening stem adapted forconnection at the top thereof to the bubble cap and a transverse supportrigidly secured to the bottom of said stem so as to permit downwardpassage of the support through said opening from above the deck andupward passage therethrough from below in the undeformed state of thesupport and having a plurality of arms extending out from said stem tobeyond the edge of the opening at points distributed about said edge,said arms providing at said points (a) a shoulder disposed forengagement with the underside of the tray to limit upward movement ofthe support, (b) an upright retaining surface adapted for resilient,frictional engagement with the interior surface of the opening torestrain the support against downward movement during assembly anddisassembly, and (c) a cam surface extending upwards from said retainingsurface, at least one cam surface being inclined generally toward thestem and at least one of said arms intersecting said edge at an angle tothe radius to the point of intersection and being horizontally resilientto reduce the diameter of the circle enclosing said retaining surfacesupon flexure of said arm when said cam surfaces engage the interiorsurface of said opening during upward movement of the support, all partsof said support above said retaining surface being situated within acircle having a diameter less than that of the circle enclosing saidretaining surfaces, whereby said support is restrained against downwardmovement solely by said resilient frictional engagement.

8. A hold-down according to claim 7 wherein all arms are resilient andintersect the edge of the opening at angles to the radii totherespective points of intersection and all arms have cam surfacesinclined generally toward the stem.

9. The combination with a contacting tray deck having an openingtherein, of a bubble cap situated over said opening and having a partthereof in upwardly supported relation to the deck, and a hold-downtherefor comprising a vertical fastening stem aligned with said opening,screw-threaded means securing said bubble cap releasably to the stemagainst upward movement, and a transverse support within said openingsecured to said stem, said support and stem being insertable andremovable through said opening from above the tray in the undeformedstate of the support and said support including a plurality of arms inengagement at the outer ends thereof with said deck at points spacedalong the periphery of said opening and providing at each of said points(a) a shoulder in engagement with the underside of the tray to limitupward movement of the support, (b) a lateral retaining surface infrictional, resilient engagement with the interior surface of saidopening to restrain the support against downward movement duringassembly and disassembly, and (c) a cam surface extending upwards fromsaid retaining surface, at least one cam surface being inclinedgenerally toward the stem and at least one of said arms being resilientto reduce the size of the closed plane geometric figure enclosing saidretaining surfaces upon exure of said one arm when said cam surfacesengage the interior surface of said opening during upward movement ofthe support, all parts of said support above said retaining surfacesbeing situated within a closed plane geometric figure smaller than asimilar iigure enclosing said retaining surfaces.

Ackroid June 22, 1948 Kelley June 6, 1950

1. A HOLD-DOWN FOR FASTENING A BUBBLE CAP OVER AN OPENING IN ACONTACTING TRAY DECK, COMPRISING AN UPRIGHT FASTENING STEM ADAPTED FORCONNECTION AT THE TOP THEREOF TO THE BUBBLE CAP AND A TRANSVERSE,RESILIENT SUPPORT SECURED TO THE BOTTOM OF THE STEM SO AS TO PERMITDOWNWARD PASSAGE OF THE SUPPORT THROUGH SAID OPENING FROM ABOVE THE DECKAND UPWARD PASSAGE THERETHROUGH FROM BELOW IN THE UNDEFORMED STATE OFTHE SUPPORTT AND HAVING A PLURALITY OF UPWARDLY DIRECTED ABUTMENTSDISPOSED TO ENGAGE THE UNDER SIDE OF THE DECK TO LIMIT UPWARD MOVEMENTOF THE SUPPORT, A PLURALITY OF LATERAL RETAINING SURFACES ON THERESILIENT SUPPORT URGED RESILIENTLY OUTWARDS FOR FRICTIONAL ENGAGEMENTWITH THE INTERIOR SURFACE OF SAID OPENING, AND CAM SURFACES ABOVE SAIDRETAINING SURFACES ON THE SSUPPORT MERGING THEREWITH TO MOVE SAIDRETAINING SURFACES RESILIENTLY INWARDS BY ENGAGEMENT OF SAID CAMSURFACES WITH SAID INTERIOR SURFACE OF THE OPENING, ALL PARTS OF THESUPPORT ABOVE SAID RETAINING SURFACES BEING SITUATED INWARDS WITHRESPECT TO THE RETAINING SURFACES, WHEREBY SAID SUPPORT IS RESTRAINEDAGAINST DOWNWARD MOVEMENT DRUING ASSEMBLY AND DISASSEMBLY SOLELY BY SAIDRESILIENT, FRICTIONAL ENGAGEMENT.